I am trying to get started on an attempt to fix my adaptive cruise control since I use the truck to commute 100+ miles everyday.
Looking at older posts there seem to be no real conclusions on how the problems were fixed. I plan on documenting my findings as I move forward trying to get ASCD to work with everyone's help (I am starting to get more involved into DIYs and my electrical knowledge is average at best).

I was looking at EL-269 in the FSM and my problem matches "ASCD cannot be set. (“SET” indicator lamp does not blink.)" i.e. the green and orange lights come on. However, pressing set button does nothing. An older thread suggested that the adaptive function is by-passed if I were to hold the set button for about 1.5 seconds. I have tried this and it does nothing.

Next, the table on EL-269 lists the following 3 areas for potential concern:
1. ASCD BRAKE/STOP LAMP SWITCH CHECK -> EL-272
2. ASCD STEERING SWITCH CHECK -> EL-273
3. VEHICLE SPEED SENSOR CHECK -> EL-274

So, step 1, could someone tell me where the ASCD control unit harness connector is located? Is this the one that's on the cruise unit in the engine bay?

Poked around a little bit more. I found the location of the ASCD servo, the motor and the 4 pin connector....but I cant seem to find the 8 pin connector. Any pointers where this might be located?

Can someone verify that this diagram is accurate? The ASCD control is in the trunk area?????

https://www.infinitipartsdeal.com/Page_ ... %20control

If this is the case, how do I disassemble the cargo panel to access this controller?

Can someone verify that this diagram is accurate? The ASCD control is in the trunk area?????

https://www.infinitipartsdeal.com/diagr ... 53_005.png

If this is the case, how do I disassemble the cargo panel to access this controller?

Edit: For future reference, it is p/n#18995 under view "P".

I have no idea of the real locations, but that website definitely hasn't led me astray yet.

See if this helps with your panels. IIRC, just start with the push pins at the very back edge, the ones keeping the trunk sill in place
topic618198.html

brickbox wrote: ↑

Thu Feb 01, 2018 1:57 pm

Can someone verify that this diagram is accurate? The ASCD control is in the trunk area?????

https://www.infinitipartsdeal.com/diagr ... 53_005.png

If this is the case, how do I disassemble the cargo panel to access this controller?

Looks like it might be behind the panel and near the rear left side door.



For panel removal look here, p.29
http://www.nicoclub.com/service-manual?fsm=QX4/2002/BT

Thank you EdBwoy and 04pathse!
Its currently 10 degrees outside - waiting for it to warm up a little bit before I attempt removing that panel to further diagnose the ASCD. From the looks of it, I should be able to remove 3 fasteners and pry away that lower panel to access the control.

More updates once it gets a little warmer...

EdBwoy wrote: ↑

Thu Feb 01, 2018 2:16 pm

I have no idea of the real locations, but that website definitely hasn't led me astray yet.

See if this helps with your panels. IIRC, just start with the push pins at the very back edge, the ones keeping the trunk sill in place
topic618198.html

How do I take the kick plate/scuff plate off? I can’t seem to get it to budge (haven’t tried brute force yet....)

Chaps, it looks like we might have been looking in the wrong area on the vehicle. I tore the cargo area apart and could not find "M3" brown color connector there
I found the ASCD controller and there are 3 harnesses that plug into it - M119 (white connector), M120 (gray connector) and green connector (not sure what the number is). None of them match the FSM's connector layout for M3. I even tore apart additional layers to get to the Bose amplifier. No dice

So after about 2 hours of messing around and trying to find this connector, I gave up (and it started snowing....again ) and came back to take another look at the FSM. Page EL-260 clearly shows where connector M3 is (under the driver's side dash

Can someone please guide me how to take the kick panel/under dash area off so I can access this connector?

So I'm looking at your posts and I think you have "intelligent cruise control" which automatically slows the vehicle down if you come up on traffic ahead of you. Regular cruise control is set and forget - one speed until you tap the brakes to disengage it, which is what I have.

If you have intelligent cruise control, the section for that begins at EL280, parts locations are on EL291, and wiring diagrams begin at EL292. You have a sensor located in the front bumper if you have intelligent cruise.

There are some different diagnostic tests in that section.

Am I seeing things correctly?

Oh, and I see there is a self diagnostic test at the bottom of EL313 if you have intelligent cruise. That would help!

Rockwood wrote: ↑

Sat Feb 17, 2018 7:13 pm

Oh, and I see there is a self diagnostic test at the bottom of EL313 if you have intelligent cruise. That would help!

You are right! I never scrolled that far down in the FSM. I do have the ICC and will try to take a look later today.
I read the diagnostics briefly and I have no display about the speed setting or the distance setting showing up on the dash. All I have are the green and orange cruise lights - which according to page EL282, the orange light comes on only when there is a fault in the system.

Update - ran the self diagnostics test called out on page EL-313. I got 3 error codes: 42, 103, 20 in that order. Erased the codes using the procedure called out on page EL-314 (steps 11-14). I got codes 20 and 103.

Code 103 (page EL-355) makes you refer back to code EL-20 (page EL-320). Step 1 is to check CAN communication with Consult-II. I don't have Consult.

So I proceeded to step 2 (check harness for open circuit 1). However, I cannot get connector 140 that is attached to the radar to come off!!! Any tricks? I thought you just lift the tab in the circled area and out comes the connector sliding to the right?


For the heck of it, I proceeded to step 3 (check harness for open circuit 2). With key out, I got a 0 resistance reading between pins 5 and 14 on connector 158 (white color connector at the controller in the trunk). Do I need to re-try this with the key in the ignition but in off position?

I think that is a waterproof connector. See page E7 for how it opens. They are sticky, so expect to have to play with it a bit. Probably should clean the contacts with some electrical contact cleaner for good measure.

Code 20 is telling you to test the circuit to the laser sensor. Code 103 is essentially telling you if that circuit tests ok, you need to replace the laser sensor.

Gotcha! Waiting on weather to clear and I will dive back in.

Rockwood wrote: ↑

Sun Feb 18, 2018 3:38 pm

I think that is a waterproof connector. See page E7 for how it opens. They are sticky, so expect to have to play with it a bit. Probably should clean the contacts with some electrical contact cleaner for good measure.

Code 20 is telling you to test the circuit to the laser sensor. Code 103 is essentially telling you if that circuit tests ok, you need to replace the laser sensor.

So I was able to mess around a little bit yesterday with the car.
Per test 2 " CHECK HARNESS FOR OPEN CIRCUIT 1" on page EL-321, I got a resistance readings between 61.4 ohms and 61.9 ohms over 3 different attempts.
Since this classifies under "ok" test result - does this mean I have to replace the ICC sensor?

For the heck of it, I tried the voltage test on EL-322 and the continuity tests on EL-323 and they checked out fine. Which would mean that the controller in the trunk is working fine.
However, I went back to test #3 "CHECK HARNESS FOR OPEN CIRCUIT 2" on EL-321. I tried multiple times to get a resistance reading between pins 5 and 14 of connector 158 (white color). I could not get any reading except the one time where it read 121-122 (I think the probe tips on my DMM are too wide to get them into the connector for consistent reading).

So:
1. Does everything I have written above indicate a bad sensor?
2. The part number listed for the radar/sensor is 284373W420 on https://www.infinitipartsonline.com/oem ... wtdjYtZ2Fz
However, when I check on eBay, all parts are listed as either 28437 AR220 A or 28437 AR211 B. There are a bunch of these sensors under 02-04 M45 and Q45 but nothing under QX4.

Would either of the above work?

Bueller Bueller?

Anyone know if the above p/n#s are interchangeable? Don't really want to spend $1000 getting a new radar.

Yes, it looks like you got acceptable resistance readings for both tests on the sensor communication circuit, and that means the sensor is bad. You can redo the second test where you got 121 ohms if you want - use a sewing pin and stick it in the connector if you need to - but your tests indicate a bad sensor.

Codes 20 and 103 gave you two possibilities: either a bad communication circuit or a bad sensor. You tested the circuit as ok, so the sensor will be the problem.

Your parts link is correct: the sensor is the same fot 2001 to 2003 QX4's per the info at the bottom of that page.

Ok, I went to car-part.com and put in 2002 QX4, picked adaptive cruise projector as the part, and when the search box came up I selected years 2001 to 2003. I got 5 results, so this is a rare part.

Prices vary from 500 to 1000 and they will come with only very short warranties. If you decide to try a used one, make sure you can return it if it is DOA.

They do not show sensors from any other vehicle in their list, so sensors from other Infinitis are not considered interchangable.

Probably going to be an expensive fix.

One last check - page EL-293 shows fuse 11, a 7.5 amp fuse for the sensor. But that fuse runs other things, so I expect you would know it if it had blown. Worth mentioning I guess, just for the record!

You can check for 12 volts at pin 1 on the sensor connector just to be 100% sure the sensor is getting power.

Checked that fuse - its fine. Checked the other ones related to cruise control as well - they all check out ok.
I will give the sewing needles trick and power on terminal 1 a shot over the weekend. Seem unlikely to me it wont be getting power because its able to transmit the error codes (which I can erase and get it to come back just by cycling ignition. Code 20 comes back immediately and code 103 comes back only if I turn on the cruise system hitting the on/off button).

Little disappointed that I wont be able to get the cruise working for cheap but I am not sure if I want to spend that kinda money especially since I need to fix the leaky VCG and I think my RMS has started to leak

Don't know if this will work or not but I saw that someone was having the same issue as you with the ICC and they asked if there was a way to disable the ICC so that the cruise control will still work and someone responded that it is possible to disable the ICC by pressing the "distance" button.

I had sometime to check out the car today. And I do get power at pin 1. So......its the radar that needs replacement. I posted an ad in WTB section of classifieds.

Thats a good suggestion @04pathse, at this point I would be happy getting regular cruise control. Is there a specific sequence when the distance button must be pressed? My understanding is that the amber cruise light pretty much disable the cruise system and it comes on as soon as I hit the on/off button.

Perhaps -> (1) on/off button; (2) distance button; (3) set button would work?
Idk, I guess I could give it a shot tomorrow. Or what if I just disconnect the radar sensor connector? Would that force the system into regular cruise control?

brickbox wrote: ↑

Sun Mar 04, 2018 4:30 pm

Perhaps -> (1) on/off button; (2) distance button; (3) set button would work?
Idk, I guess I could give it a shot tomorrow. Or what if I just disconnect the radar sensor connector? Would that force the system into regular cruise control?

Tried the above sequence during today morning's commute. No dice.
Owner's manual makes no mention of being able to switch to regular cruise control (unlike the later Infiniti's that seem to have this option).

Wikipedia states that the cruise control on the QX4 was shared with the Q45. Anyone here know the differences in the radars between the 2 vehicles?
Parts numbers are different but I couldn't find anything about cross compatibility.

It is possible they are the same. They do look the same. You could probably get to yes by doing some research / comparisons.

Download the 2002 Q45 EL manual. If they are the same system, the Q45 service manual for adaptive cruise will be the same as the one for the QX4. The various tests and specs will match up. In some cases, you will probably have different wire colors.

The ICC sensor plug for the Q45 must match the one for the QX4. So the wiring diagram on page EL293 for the ICC sensor must match.

The magic happens on pins 3 and 6 of the ICC sensor. You tested that circuit for resistance and it checked out ok. The specs (ohms resistance) and the test for that circuit on the Q45 must be the same.

There is a list of specs on page EL306 for the operating voltages on CAN H and CAN L circuits (those are pin 3 and 6 on the connector). Those again must be the same on the Q45.

If all of that matches, you can be pretty sure the operating specs for the ICC sensor are the same, and therefore the Q45 sensor will probably work.

Then you can decide whether to take the shot. There are more Q45 sensors out there than QX4 sensors, and at a better price.

I'd say you have a good shot they are the same.

Sounds logical! Going to do this over the weekend. Fingers crossed.....

Rockwood wrote: ↑

Mon Mar 05, 2018 9:57 pm

Download the 2002 Q45 EL manual. If they are the same system, the Q45 service manual for adaptive cruise will be the same as the one for the QX4. The various tests and specs will match up. In some cases, you will probably have different wire colors.

The ICC sensor plug for the Q45 must match the one for the QX4. So the wiring diagram on page EL293 for the ICC sensor must match.

The magic happens on pins 3 and 6 of the ICC sensor. You tested that circuit for resistance and it checked out ok. The specs (ohms resistance) and the test for that circuit on the Q45 must be the same.

There is a list of specs on page EL306 for the operating voltages on CAN H and CAN L circuits (those are pin 3 and 6 on the connector). Those again must be the same on the Q45.

So the pins for CAN H and CAN L (3 and 6) match between the QX4 and Q45. I also checked the resistance values that are called out for the steering switch and they are the same.
HOWEVER:
1. DTC 20 for the Q45 (page ACS-70) does not call out any specific resistance values.
2. Wiring diagram for QX4 (EL-303) looks different that the one for the Q45 (ACS-47 are not exactly the same). Can someone please check and compare these? My wire diagram reading skills are admittedly poor.
3. The pin outs for the sensor/radar are same between the QX4 and the Q45.
4. The Q45 also uses 3 connectors on the controller (white, green and gray - although under different connector #s).
5. Resistance values between pins 3 & 6 at the radar for QX4 is 54-66ohms (EL-321). The Q45 FSM doesn't state anything except to refer to LAN-42. In the LAN section of the Q45 FSM, on page LAN-63, it says 54-66 ohms between pins 3 & 6 of the connector!!

So as long as someone can help me with comparing the main schematics of the QX4 (EL-303) and the Q45 (ACS-47), I think I have a shot here at using the Q45 radar/sensor.

As always insight/advise is appreciated.

I took a look at this, and I guess there is a short answer and then a long answer.
Short answer is I think it is very likely the Q45 sensor works in the QX4, and are the same part.

>> Infiniti says the vehicles share the same adaptive cruise system. (But don't specifically say this part is interchangeable anywhere.)
>> The wiring pinouts on the sensor plugs are the same.
>> The operating voltages on the CANBUS sensor circuit are the same.
>> The adjustment procedure and laser aimpoints are the same for both vehicles.

If you decide to try the Q45 sensor, the Q45 mounting bracket needs to be swapped for the QX4 mounting bracket. Those brackets are adjustable, so you must be careful not to change any adjustment settings so the new sensor is aimed exactly the same as the old sensor.

The Q45 sensors ending in AR220 are the newest versions, so try to get one of those versus the earlier parts.

There is still a chance a Q45 sensor won't work. There is nothing that directly says these parts are interchangeable. However, the operating parameters are the same, and wiring is the same, and the sensors look the same. When looking at the parts diagrams for the Q45 and QX4 I noticed that the sensors have different bumper mount points. The sensor mounting brackets are not available separately, so I think the only real difference may be that a QX4 sensor or a Q45 sensor are sold with different mounting brackets, hence the different part numbers.

You should be able to plug in a new sensor, set it flat with face forward, then clear your cruise control codes and reperform the cruise control check you did earlier. You should get no codes. At that point, you can switch brackets and finish the install if all is well.

If there are no codes, but it is not performing well in traffic, you would need to have the dealer do the aiming adjustment. No way to do that yourself.
---------------------------------

Now the longer answer since this took some research. Might as well document it in case someone finds it useful in the future. For a lot of people this is the TLDR part!

>> The 2002 Q45 is a CANBUS vehicle, which replaced OBDII. QX4's are OBDII. In CANBUS all the vehicle computers are connected to a common data link, much like a regular PC. Different systems, so the Q45 and QX4 Intelligent Cruise Controller (Computer) are not the same. The 2002 QX4 ICC however, has a CANBUS sensor operating circuit designed into it which appears to mimic the Q45 CANBUS. (CANBUS circuits are designated by alternating black and white dashes in Infiniti / Nissan cicuit diagrams.)

The sensor circuit works on pins 3 and 6, and has the same operating voltages as the Q45. This is what allows the same sensor to be used on both vehicles. See page EL-306 for the QX4 and page ACS-56 for the Q45 where the sensor circuit parameters are listed. Pinouts are also listed here, and are the same (pins 1,3,4,6).

>> Resistance test for the sensor circuit are the same on both vehicles: 54 to 66 ohms. See page EL-321 for the QX4 and page LAN-64 for the Q45. There is a resistor in the QX4 wiring diagram for this cicuit which is there to mimic the resistance in the Q45 CANBUS circuit I believe.

>> I located an Infiniti dealer tech bulletin that discusses how the technician is supposed to set up the laser adjustment tools for the sensor. This bulletin indicates that the Q45 and QX4 are adjusted to the same specs. Link is here:

http://www.infinitig37.com/TSB/1RB14.pdf

>>Turns out that the staement that the adaptive cruise system is shared with the Q45 came from the 2002 QX4 press release about the vehicle. That statement is a marketing statement, and is only partially true. The underhood components are in many cases the same, but the cruise control computer is different as it is CANBUS. The laser sensor appears to be the same other than the brackets as discussed above.

>> It looks like early QX56's may use this same sensor, but I did not try to verify that.

End of TLDR!

Part ordered off a 2003 Q45 and should be here end of this week/beginning of next. Keeping fingers crossed on the compatibility.

So I cant get the connector off on the vehicle! I was literally tugging against the wire (from the radar) and holding the vehicle wire harness end steady (with the tab lifted up). The damn thing refuses to budge. 45 minutes later - I still have nothing.
Any tricks?